STMicroelectronics L78L06ACD

Overview

L78L06ACD from STMicroelectronics is a three-terminal positive linear voltage regulator delivering a fixed 6 V output at up to 100 mA, featuring internal current limiting, thermal overload protection, and short-circuit protection. It requires no external components, operates with a 1.7 V dropout voltage, and maintains ±4% output tolerance over 0–125 °C junction temperature. It is used for local on-card regulation in microcontroller power domains and sensor interface circuits.

For engineers reviewing the L78L06ACD datasheet, L78L06ACD pinout, L78L06ACD application, or L78L06ACD equivalent, key selection criteria include output accuracy (±4%), quiescent current (6 mA typ.), thermal shutdown behavior, TO-92 package thermal resistance (R_thJA = 200 °C/W), and compatibility with low-noise analog subsystems requiring <50 µV RMS output noise.

Technical Context

The L78L06ACD implements a monolithic silicon-based series pass regulator architecture with built-in foldback current limiting and thermal shutdown circuitry. Its internal reference and error amplifier maintain stable 6 V output across input voltages from 8.5 V to 20 V and load currents from 1 mA to 100 mA.

It achieves 39–46 dB supply voltage rejection at 120 Hz under 40 mA load, with 50 µV RMS output noise (10 Hz–100 kHz bandwidth), and exhibits 100 mV max load regulation over full current range at 25 °C - confirming suitability for noise-sensitive analog front-ends and digital logic rails.

Key Specifications

Pinout & Package

Supplied in TO-92 package (JEDEC TO-226AA), with 3 leads: Pin 1 = V_OUT, Pin 2 = GND, Pin 3 = V_IN. Thermal resistance is R_thJA = 200 °C/W (no PCB copper heatsink) and R_thJC = 15 °C/W, enabling 100 mA operation only with minimal ambient rise when ambient ≤50 °C.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar fixed-output linear regulator applications.

Compared with LM78L06ACZ and MC78L06ACP, the L78L06ACD offers optimal cost/performance balance for commercial-temperature applications requiring TO-92 through-hole assembly, lower quiescent current than LM78L06ACZ, and simpler qualification path than MC78L06ACP's extended temp grade.

Availability

L78L06ACD is available at Aetrix Electronics and suitable for industrial sensor nodes, IoT edge peripherals, automotive body control modules, and microcontroller core rail applications requiring stable component supply and long-lifecycle support.

Supply support for L78L06ACD includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, MCU, power, and sensing solutions for industrial, automotive, and consumer markets.

The L78L series belongs to ST's legacy linear regulator product line, engineered for cost-sensitive, high-reliability applications where simplicity, ruggedness, and proven performance outweigh advanced features like enable pins or adjustable outputs.

FAQ

What is the maximum input voltage for continuous operation of L78L06ACD?

The absolute maximum DC input voltage is 30 V for VO = 6 V, per STMicroelectronics' datasheet Table 1. However, for continuous 100 mA operation at 25 °C ambient, VI must not exceed 20 V to avoid exceeding the device's thermal limits in TO-92 packaging - due to R_thJA = 200 °C/W and 1.7 V dropout causing ≥1.7 W dissipation at 20 V input.

Does L78L06ACD require input and output capacitors?

Yes: a 0.33 µF ceramic capacitor is required between VIN and GND, and a 0.1 µF ceramic capacitor between VOUT and GND, placed as close as possible to the device pins. These stabilize the regulator and prevent oscillation; omitting them risks instability, especially under dynamic load conditions.

Can L78L06ACD be used in parallel to increase output current?

No - the L78L06ACD lacks current-sharing capability and has no built-in balancing mechanism. Parallel connection causes unequal current distribution due to output voltage tolerances (±4%), leading to thermal runaway in the unit with slightly higher output voltage. Use a single higher-current regulator or external pass transistor instead.

Is L78L06ACD RoHS compliant and halogen-free?

Yes: per STMicroelectronics' official product change notification (PCN) and packaging data, L78L06ACD in TO-92 package meets RoHS Directive 2011/65/EU and is halogen-free (IEC 61249-2-21 compliant), with lead-free matte tin terminal finish and epoxy molding compound free of brominated flame retardants.